Download Week 4 Evolution Ideas and Evidence

WEEK 4
MECHANISMS
AND
DEFINITIONS
COURSE REVISION
 Due to the extensive amount of material within evolution I will
be splitting the last lecture into two separate classes this
week and next week (the 16 th )
 This week we’ll look at what evolution is and the mechanisms
behind it. Next week we’ll deal with the evidence for evolution
and (if there’s enough time) the story of Charles Darwin and
evolution
 I feel this will be easier for me to successfully converse the
idea of evolution in the short time we have. University courses
take dozens of hours and they still only scratch the surface of
the vast field of evolutionary biology so I feel another class
will be crucial in communicating this fascinating field of study
COURSERA
 Lots of free university courses without any tests or exams (though
they are available for students wishing to earn a certificate of
accomplishment)
 Video lectures provide instruction on learning almost anything you
want
 https://www.coursera.org /
STAR TALK RADIO
 Hosted by Neil Degrasse Tyson
(an astrophysicist), this radio
podcast explores questions
regarding the universe and
astronomy
 Many shows collect fan
questions about certain topics
(Venus, black holes, new
discoveries ect) while others
interview celebrities and people
in science
 Great for learning about physics
and astronomy
 http://www.startalkradio.net /
A BRIEF RECAP
 Class 1: Evolution and Religion
 Worldwide most Christians are evolutionists
 In the American scientific academy, roughly 95% believe in evolution and
roughly 40% believe in both a personal God as well
 This controversy is so profound in America (and nowhere near as much of
an issue in the rest of the scientifically advanced nations) because it has
its roots in American Christian Fundamentalism
 Class 2: Creationism and the Teach the Controversy Campaign
 “Creationism” covers a wide range of beliefs with varying acceptances of
modern science but all hold an anti-evolution stance
 There have been several famous hoaxes in evolutionary science but all
have been uncovered by scientists and not a single one by creationists
 “Teach The Controversy” was an Intelligent Design campaign designed to
avoid scientific scrutiny by advocating that the controversy be taught.
This controversy does not exist in the scientific community and public
controversy are not grounds for requiring it be taght (eg Holocaust
Denial)
 Creationist organizations continue to target primarily the public in
relaying their ideas, rather than convincing the scientific community first
as any other scientific idea would do.
 Class 3: Science and Creation Science
 Science uses evidence to construct testable explanations and
predictions of natural phenomena
 Theories are the highest form of understanding, they help us explain
and understand facts. They are constantly tested and are rigorously
examined to ensure accuracy
 These ideas in science remain tentative, since there could always be
information that we haven’t observed yet but which would disprove
the theory
 Creation science is completely dogmatic in their methods: absolutely
no evidence at all will prove them wrong
 Creation science is not concerned with what the evidence shows, all
they care about is supporting their pre-conceived beliefs
 Creation science is the antithesis of science in that it opposes and
rejects the principles that make science accurate, self -correcting,
objective, explanatory and useful.
SCIENTISTS MUST ADMIT WHEN THEY’RE
WRONG
 In 1981 , Stephen Hawking proposed that black
holes violated the Conservation of Information
(a fundamental law of physics)
 Conservation of Information: information cannot be
lost eg: A nuclear bomb will blow up everything, but
down at the core of physical principles, the
information (atoms ect) has not left the universe, it’s
still there no matter how scrambled
 Black holes (according to Hawkings) however, would
devour matter and leave no record. Rather than
scramble information, they would obliterate it.
 If he was right, than most of modern physics
would be seriously flawed
 Leonard Susskind, was skeptical and in 2009
he was able to complete his idea to explain
information conservation in black holes.
Stephen Hawking conceded that Susskind was
right and black holes do not violate the
conservation of information
EXTRAORDINARY CLAIMS REQUIRE
EXTRAORDINARY EVIDENCE
 GFAJ-1: a strain of bacteria found in Mono
Lake California that can tolerate deadly levels
of arsenic
 The authors of a 2010 paper published in
Science, claimed it could thrive in a high arsenic environment without metabolizing
phosphorus (an element essential to ALL
forms of life) by incorporating arsenic into
DNA instead
 If true, it would mean that this organism is
unlike anything else on this planet, possibly
so different as to be considered “alien”
 To encourage thorough investigation, the
authors made the strain available upon
request and Science made the paper freely
available
 Subsequent studies and experiments showed
that this strain does require phosphorus and
goes to extraordinar y lengths to obtain it
SCIENTISTS DON’T GET TO BELIEVE IN THEORIES
 Scientists don’t get a choice in
“believing” in theories, they’re an evident
conclusion and even when we don’t like
that conclusion we can’t avoid its truth
 Eg. Birds (and penguins especially) have
been the hallmark of monogamy in the
animal kingdom as many form life -long
par tnerships
 However, countless studies are showing
that extrapair paternity is a widespread
phenomenon and the frequency varies
greatly
 Roughly 20% of Black-headed gull chicks, 35%
of eastern blue bird chicks and as much as
50% of tree swallow chicks are due to these
parental affairs
 Of interesting note is that these
extramarital af fairs are sometimes not
for producing chicks. Female Adelie
penguins may use copulation to bar ter for
stones for nest materials, indicating a
type of animal prostitution.
 We may wish to think of birds as symbols
of faithful chastity, but we cannot given
the evidence
EVOLUTION: WARNING
 Biology is messy; it’s a complicated field of
study with numerous simultaneously
interacting mechanisms and processes
 In order to really understand evolution, you
need a some understanding of paleontology,
geology, genetics, morphology,
biochemistry, developmental biology ,
ecology and many more
 These two classes will be the most
technical of this course so please don’t be
discourage if it’s hard to understand
 ALWAYS ASK QUESTIONS if you don’t
understand something or if you want to
know more. Please don’t be shy in asking, I
want this course to be as clear and helpful
as possible and it’s likely that if you have a
question, someone else is thinking the
same thing too.
INTRO TO GENETICS
 DNA: the molecule which encodes the genetic instructions
used in the development and function of ALL life
 DNA’s ladder structure: the “rungs” of the ladders are bases and
there are four different bases in DNA, represented by the letters A, G,
C and T
 DNA is the material we inherit from our parents and that is
why we share similarities with them
GENES
 Gene: a stretch of DNA that codes for a protein
 Proteins perform various functions in the body including but not
limited to determining physical traits (such as hair color, number of
limbs/digits), directing development (from a single cell to a full
organism) and producing all the needed elements for the thousands
of the biochemical processes that comprise life
 Genes are composed of certain sequences of the 4 DNA bases
(G,C,T,A)
 Variations of genes(base sequence) (eg red hair, blonde hair ect) are
called alleles
 Although they are important, genes can comprise a very small
portion of the genome (roughly 2% in humans) as well as a very large
portion (98% in bacteria)
 Non-coding DNA can have important functions too such as regulatory sites
but some do not such as pseudogenes
WHAT IS EVOLUTION?
 Very generally, evolution means change through time
 Biological evolution (specifically) means the change in genetic
frequency within a population of organisms (i.e. it is when a
gene/allele/trait becomes more/less common in a population).
 Natural selection is the main (but not the only) mechanism by
which this genetic frequency change occurs. Darwin composed it
of four facts
Organisms show variation in traits (inheritable characteristics)
More organisms are born than can possibly survive
Some traits offer advantages in the resulting struggle to survive
Individuals with those traits are more likely to reproduce and pass on
those traits
 Successful variations accumulate over generations which are beneficial
under the conditions to which the creature is exposed




 Individuals do not evolve (since it’s the change in genetic
frequency of a population) but natural selection does act on
individuals to produce this change
CHANGE IN GENE FREQUENCY
Here we have a population of beetles in which most of them carry the allele for
green coloration. Some number of generations later, things have changed: Brown
beetles are more common than they used to be in the population
Thus evolution has occurred, since the brown gene is now more common (its
frequency has increased) while the green gene is less common (it’s frequency has
decreased
NATURAL SELECTION
 This change could be due to natural selection (there are other
mechanisms): Due to perhaps camouflage, the green beetles are
preyed upon more than the brown beetles. Thus the brown beetles
survive and reproduce more. Thus natural selection favors the
individual brown beetles and this leads to an overall population
change
EXAMPLES RIGHT NOW
 In elephants, tusks provide major advantages
(can be used to dig for food, dig up trees, self
defense and sexual display)
 However, large tusks also make the individual
more likely to succumb to poaching.
 In 1930, only about 1% of the elephants
(male and female) were born without tusks
(due to genetic mutation) in Queen Elizabeth
National Park, Uganda.
 1998 research has shown that now 15% of
females and 9% of males in the park are
being born without tusks
 Similar reports are found elsewhere
 1997 found that more than 38% of Zambian
elephants were being born without tusks. Natural
unstressed populations show roughly 2%
 The advantages of tusks are not outweighing
their risk and so natural selection is selecting
against them
EVOLUTION IN ACTION: CANE TOADS
 Introduced into Australia to deal with cane beetles but instead
ate the local insects. They are also highly toxic.
 Many Australian snakes are susceptible to poisoning from
these when they attack them as food
 The ability to eat a toad large enough for the snake to kill
itself depends on the ratio of the head size to body size
 Since smaller heads restrict the size of prey that can be eaten
and a larger body requires more toxin to kill it, snakes that
are more susceptible to toad toxin have evolved smaller heads
and larger bodies in response and these were more
pronounced the longer the snakes had been in contact with
the toads
 Snakes that are not vulnerable do not show this change
OTHER MECHANISMS OF EVOLUTION
 Sexual Selection: a special case of natural selection in which
one gender’s preferences (usually the female’s) for the other
gender’s characteristics leads to an increase in frequency of
these traits
 Eg. Peacock tails: females will mate only with males that have large
and colorful tails (thus, the genes corresponding to these traits are
continuously passed on). Over time, as females continue to choose
the biggest and most colorful tails, the average tail size and
brightness increases, leading to the current creature’s appearance
OTHER MECHANISMS OF EVOLUTION
 Migration: When individuals from one population of a species
moves to another population they often carry with them
dif ferent traits. This changes the genetic frequency of the
population
Migration
Genetic Drift
 Genetic Drif t: Random genetic fluctuation. By chance, individuals
with a cer tain trait in a population may die before they reproduce.
Thus the next generation will only have a fraction of the parent’s
alleles. This is not due to any benefit.
 Mutation: can cause parents with one trait to give bir th to of fspring
with a dif ferent trait, making the new trait more frequent than
before (ver y slow process alone)
SOURCES OF VARIATION
 In order for evolution to occur by any of these mechanisms,
variation in traits must exist in the population. So where does
this variation come from?
 1 . Mutations: these change the sequence of the bases in DNA
(G,C,T,A). These can occur during replication, by the
movements of mobile genetic elements, by viruses or by
damage to the DNA:
 Point mutation: a single base is changed ( eg C is swapped for a T).
May or may not have an effect.
 Insertions: add one or more bases.
 Deletions: removes one or more bases, or whole regions
 Amplifications: duplicate entire areas such as genes
 Fusion: genes can be fused together, creating a hybrid which may
have a unique protein product
 Mutations are only important to evolution if they occur in the
reproductive cells (eggs or sperm) since these cells will pass
on their DNA . Mutations in the rest of the body’s cells will not
be inherited
MUTATIONS AND NEW INFORMATION
 A more recent creationist claim is that mutations do not
produce “information”. This term is vaguely defined if defined
at all, but it increased information can be defined as:




Increased genetic variety in a population
Increased genetic material
Novel genetic material
Novel genetically-regulated abilities
 All of these have been observed wither in the lab or in the wild, any other
definition of information is not relevant to evolution in the first place
 Creationists will argue that mutations can only lead to the
loss of information; a counterintuitive claim, since anything
mutations can do they can also undo, thus if they can cause
the loss of information, they can also add it
MUTATIONS, FITNESS AND NATURAL
SELECTION
 Fitness: the ability to survive and reproduce
 Mutations which increase an animals fitness are beneficial
while mutations which decrease it are harmful. Mutations
which have no af fect on fitness are neutral
 Mutation rates themselves are quite low and thus do not
change a population very quickly by themselves
 But with natural selection, the process happens a lot faster:
any beneficial mutations are quickly amplified and any
negative mutations are weeded out. This allows beneficial
mutations to accumulate while deleterious mutations are kept
low. The more beneficial/harmful a mutation is, the stronger
natural selection acts to propagate/remove it.
 Neutral mutations will also accumulate over time due to no
natural selection acting against it, but it will be at the rate of
mutation itself since natural selection also isn’t favoring it.
OTHER SOURCES OF VARIATION
 2. Gene flow: movement of genes from one population to
another adding variation to the recipient population
 3. Sex: recombines genetic material from two dif ferent
parents which can lead to new gene combinations, and thus
new variety
 4. Recombination: During meiosis (the process which
replicates egg and sperm cells) the chromosomes (a structure
of DNA , protein and RNA , used to package the DNA) may swap
segments, which can lead to new alleles
 Horizontal gene transfer: single celled organisms and other
organisms can acquire new genetic material by means other
than traditional reproduction For example: taking up DNA
found in the environment, viruses may inject new DNA ,
organisms may acquire new DNA from their food
ELYSIA CHLOROCTICA (EASTERN
EMERALD SEA SLUG)
GLAUCUS ATLANTICUS (THE BLUE DRAGON
SEA SLUG)
DESCENT WITH MODIFICATION AND
COMMON ANCESTRY
 Common ancestry: all life shares a common ancestor, one from
which they are all descended. This also means that all organisms
share a degree of relationship similarity to one another (each
organism has a common ancestor with every other organism;
those that are less similar will have a more distant common
ancestor than those which are more similar)
 Descent with modification: Parent’s of fspring often look and
behave slightly dif ferent from their parents and their siblings:
They descend from their parents with modification
 This also means primarily “new” traits are the results of existing
traits being modified from the parental condition
 It also means that a lot if not most of the biodiversity (the
astounding number of dif ferent forms, shapes and traits) are due
to redundancy (changing the same structure and using it in a
novel way or changing its appearance)
BIODIVERSIT Y AND REDUNDANCY: TEETH
 Elephant tusks are elongated incisor teeth, narwhals have an
elongated canine tooth (the upper left one) while walruses have
extended both
BIODIVERSIT Y AND REDUNDANCY: RIBS
 The tor toise and tur tle shells are the results of the
ver tebrae and ribs fusing together
 Cobras raise their hoods by expanding their ribs
BIODIVERSIT Y AND REDUNDANCY
 In development, the zygote (the fusion of sperm and egg)
develops neither as male nor as female. It is gender neutral,
but produces structures that later sex hormones will change
into the dif ferent reproductive systems (these hormones
dif ferentiate the fetus in humans at about 6 weeks). This is
why male mammals have nipples
 Penises and clitorises both develop from the same tissue and
both show erectile function in response to stimulation by
engorging with blood. The labia lips and the scrotum also both
form from the same tissue, and fetal gonads will develop into
testes or ovaries
SPOTTED HYENA GENITALS
 Female spotted hyenas exploit
these similarities by enlarging
their clitoris 90% and developing
more pronounced erectile function
and the labia lips fuse to form a
pseudo-scrotum (even with fat and
tissue to resemble testicles). The
female urinary tract also runs
through the pseudopenis as does
the vaginal opening
 The similarity between the two
gender’s organs is so remarkable
that early philosophers (like
Aristotle) thought hyenas were
hermaphrodites (creatures with
both sex organs) and researchers
today can’t distinguish the genders
visually.
BIODIVERSIT Y AND REDUNDANCY
 Despite its exceptionally long neck, giraffes still have the
same number of neck vertebrae as other vertebrates do
(including us) , they’ve just modified them to be longer
HOW DO NEW SPECIES ARISE
 The process of how new species arise is called speciation. It has
been observed so many times that we’ve had to distinguish
between the number of different ways it can occur but in order to
know how a new species arises, we must know what a species is
 This is not easy. Generally a species is defined as the largest
group of organisms that can successfully breed and this works
most of the time. However, some organisms which we would
consider separate species can still reproduce (such as polar and
grizzly bears), leading to a problem in biology called “The
Species Problem”
 Creationists have pointed to this to demonstrate that since we
cannot define species biologically, they should not be expected
to define their “kinds” either. However, this kind of pattern is
exactly what we should expect given that species are continually
evolving (it would blur the distinction between them). Created
kinds on the other hand, should be distinct and readily
identifiable if they were created separately, but they aren’t
T YPES OF SPECIATION
1.ALLOPATRIC SPECIATION
 The most common
 A population of individuals becomes isolated from the parental
population and separated by a barrier, meaning that the two
populations can no longer interbreed
 Since the two populations can’t interbreed, they can’t share
genetic traits; therefore, a beneficial mutation in one population
will not be able to travel to the other
 Over time, the two populations acquire more and more mutations
and new traits that the other population does not. This
successive accumulation of different traits over time, leads to
the populations becoming fundamentally different from one
another. If they diverge so much that they can no longer
reproduce, the two populations can come into contact again but
continue to diverge.
 But if the barrier is removed before reproductive isolation, the
two populations can resume breeding; traits and mutations are
shared once again and the two populations recombine into a
single species
ALLOPATRIC SPECIATION
Here we have a population of beetles that have been separated, accumulate
different mutations and traits, to the point that the two populations become
sufficiently different to be considered separate species
2.RING SPECIES
 In species with huge geographical ranges (such as sea birds),
a single population can extend to such great lengths, that the
organisms at one end of the population don’t mate with the
individuals at the other end
 Being dispersed over such a wide range can also mean that
there are dif ferent environmental factors acting at each
geographical area, leading to dif ferent pressures and
dif ferent
3. PLOIDY AND 4.ASSORTATIVE MATING
 New species can also arise without geographic isolation, and
this is one of the ways
 Very common in plants
 In normal gamete (sex cell) formation, half of the organism’s
DNA is packages inside them. By mutation, a gamete cell may
instead contain a full copy. If the plant self fertilizes, it will
produce a plant with twice the normal genetic material and
these of fspring will be unable to reproduce with the original
population.
 Snails can also show this: if a mutation reverses the spiral
form of the snail’s shell, they will be unable to mate
 Assortative Mating: if dif ferent females in a population begin
to favor dif ferent male characteristics, the population can
begin to diverge
WHAT EVOLUTION IS NOT
 The controversy regarding creationism as well as a general
lack of education on the subject has led to great confusion
regarding evolution. It is important to know both what
evolution is and what it isn’t and why
1.EVOLUTION IS NOT PROGRESS
Evolution does not have a goal in mind; it is not a ladder system. Instead it is a
continuously branching tree, with organisms changing all the time to suite whatever
requirements natural selection puts on them. Sometimes that will be towards new
forms, other times it will be a regression back. The organisms alive today are not
“better” than those in the past, they are just different. Complexity has generally
increased over time but it by no means needs to
REGRESSION “BACKWARDS”
 On islands without predators (or in similar instances where
flight is not required) birds have evolved the loss of flight and
some have lost their wings entirely
 Flight is the most energetically expensive method of travel so
if an animal can do without it they will
REGRESSION “BACKWARDS”
 Parasites are an excellent example of evolution from
complexity to simplicity
 They have lost much of what they would need in order in to
live independently as result of their dependence on their host:
if their host can supply the parasite with what they need, than
there is no need to waste energy generating it for itself
 Some ant species (such as Polyergus rufescens) raid other ant
specie’s nests and abduct their larvae. They then raise these larvae
into worker which care for them. These species have become so
dependent on their slaves that they have lost almost all ability to
feed themselves and will die without them
REMEMBER THAT BACTERIAL
STRAIN IN MONO LAKE?
 It could live in a lake that has one of the highest arsenic
concentrations in the world. No “complex” organisms can do that
 In fact, there are whole groups of microbes which stake out their
lives in some of the most inhospitable locations on earth (they’re
called extremophiles), including extremely acidic/basic
conditions, conditions without oxygen, extremely salty conditions
and at temperatures between 45 -122 degrees Celcius.
 If the earth were to drastically shift its environment to more
extreme conditions, the “complex” organisms would not be the
survivors. Being simple has its advantages
 Like any trait, the advantages of complexity is dependent on the
environment; change the environmental conditions and you can
change which traits are advantageous
 Stephen Jay Gould (evolutionary biologist): “Life is a
copiously branching bush, continually pruned by the Grim
Reaper of extinction, not a ladder of continual progress ”
2.INDIVIDUALS DON’T EVOLVE
 As said before, natural selection operates on individuals in
that the environment exerts pressures, meaning some
individuals reproduce more than others
 Since some individuals reproduce more than others in a given
population, their genetic traits will become more common
over time (over successive generations)
 This leads to change in the population which is what evolution
is
3. NATURAL SELECTION DOESN’T PLAN
FOR THE FUTURE
 Natural selection only acts in the present, as a result it has no
way to plan for future changes. This is why more than 95% of
all life that has ever existed is extinct; when drastic change or
even mild change that lasts too long occurs not a lot of
organisms are prepared for it and many go extinct as a result
 In this way, structures do not evolve with a future goal
function in mind (eg feathers did not evolve for flight initially
and gills didn’t evolve for breathing initially). Instead their
structure is often modified to suit a new function, a process
known as exadaptation
 Gills evolved from structures originally used for filter feeding which
were then repurposed for respiration. This is reinforced by the fact
that some organisms, such as oysters, still use their gills for both
functions
FEATHERS
 Many dinosaur species had feathers, as
indicated by fossil impressions (some so
well preserved that they have even
preserved the cells responsible for color
and have allowed scientists to
reasonably estimate the coloration)
 However, not all were suited for flying
and some species were too large to fly
 Sinosauropteryx (pictured bottom) was
covered in primitive feathers but were likely
used for insulation
 Ornithimimus adults had large feathers on
their forearms, forming a sort of half wing,
likely used for sexual display
 The fact that feathers are used for more
than flight are seen in today’s flightless
birds, such as ostriches (insulation and
display) and penguins (insulation)
WINGS AS BROOD PROTECTION
Here, a Citipati uses its wings to shield its eggs from a sandstorm which ended up
killing and fossilizing it
4. NATURAL SELECTION CANNOT
PRODUCE PERFECTION
 This is because improving one trait may compromise another
trait. These are known as trade -offs
 Natural selection also acts on existing variants which may
already have problems
 Some forms of evolution may actually favor structures that
are impractical or even detrimental
 Natural selection may be unable to select against certain
degenerative traits
IMMUNE SYSTEM TRADE-OFFS
 A healthy immune system is
extraordinarily helpful in avoiding
disease and dealing with infections
 It is based upon the destruction of
material considered to be foreign.
Unfortunately, this includes the
developing fetus if a woman is
pregnant (since half of its DNA comes
from its father, the mother’s immune
system can see it as foreign)
 If the mother’s immune system can
reach the developing fetus, it can
attack it and cause a miscarriage
 In addition to the placenta acting as
a immunological barrier, the mother’s
immune system’s sensitivity is
decreased to avoid this but this
leaves the mother more vulnerable to
infectious diseases
THE SPANISH FLU (1918)
SUBOPTIMAL DESIGN
SUBOPTIMAL DESIGN
 The recurrent lar yngeal ner ve star ts at
the brain and inner vates the lar ynx. In
tetrapods it loops down around the
ar teries coming of f from the hear t,
making an unnecessar y detour.
 This ner ve originated in fish as a direct
link from the brain to gills near the
hear t (fish don’t have necks so the
looping around the hear t provides a
direct route)
 However, when tetrapods evolved from
the lobe-fined fish and star ted
developing necks, this looping became
exaggerated since the hear t was
pushed down into the chest and the
brain and lar ynx were pushed up.
 This is a minor deviation in humans but
in giraf fes the ner ve has to travel 2
meters down and 2 meters back up to
reach a destination about two inches
from its star ting point
THE IRISH ELK (MEGALOCEROS)
 Sexual selection
(female’s preference
to mate with males
with certain traits) led
to the evolution of
huge antlers
 One of the likely
factors that drove it to
extinction, was
climate change which
led to vegetation
change
 Growing huge antlers
requires LOTS of
nutrients and with the
loss of vegetation to
provide those
nutrients, they were
unable to meet these
demands
ALZHEIMER’S AND HUNTINGTON’S
DISEASE
 These genetic diseases are weakly selected against by natural
selection despite their negative ef fects
 It is likely that natural selection would be unable to get rid of
these and similar diseases from the population
 Why?
5. NATURAL SELECTION DOESN’T ACT
FOR THE GOOD OF THE SPECIES
 Natural selection acts on individuals and can select for selfish
behavior
 Eg. Lion infanticide
 When a new male lion takes over a pride of lions, one of the first
things he does is to kill the cubs of the preceding leader. This not
only brings the females back into heat but it also ensures that the
only cubs he provides for are the ones carrying on his genetic legacy
 This is not good for the species as a whole, since they
ef fectively make all the time and energy spent on raising
those killed cubs useless but it does ensure that the
individual’s genes are passed on and so natural selection
favors it.
 However, natural selection can also select for altruism in
social groups, as well as cooperation
6. EVOLUTION IS NOT RANDOM
 Though the mutations that produce the variation in
populations arise by chance, evolution itself IS NOT RANDOM
and absolutely NO evolutionist claims that the complex
structures arose by chance
 Natural selection is what chooses from the random variation
and leads to the formation of complex structures but selection
is the very opposite of random
 Variation combined with selection in laboratory settings has
produced complex formations including circuits and robots. It
has also been useful in designing new drugs, designing better
enzyme detergents and as genetic algorithms for many other
applications
7. ANIMALS ARE NOT THE ONLY THINGS
TO EVOLVE
 ALL life evolves, including animals, plants, fungi and single
celled organisms
 Viruses (not technically life) can evolve as well
 In fact anything can evolve, so long as it reproduces, mutates
and selection is applied
FURTHER READINGS
 A complete introductory guide to evolution
http://evolution.berkeley.edu/evolibrary/article/evo_01
 How Stuff Works: How Natural Selection Works
http://science.howstuf fworks.com/life/evolution/natural selection.htm
 Your Inner Fish: A PBS documentary based on the bestselling
book by Neil Shubin
 Why Evolution Matters
https://www.youtube.com/watch?v=V6zaRW5dL5w&feature=yout
u.be
 How Evolution Works
https://www.youtube.com/watch?v=hOfRN0KihOU
 What is Natural Selection
https://www.youtube.com/watch?v=0SCjhI86grU
 How Does Evolution Work
https://www.youtube.com/watch?v=hOfRN0KihOU
 What is Evolution
https://www.youtube.com/watch?v=GhHOjC4oxh8
REFERENCES
 Arsenic-Tolerant Bacteria Need Phosphorus
http://www.nature.com/news/arsenic -life-bacterium-prefersphosphorus-after-all-1.11520
 Through the Wormhole (S01E02): The Riddle of the Black Hole
 Monogamy and Parental af fairs in birds
http://beheco.oxfordjournals.org/content/2/4/339.abstract?i
jkey=ccf6846ca4ad67deef5abcf31b28efdd94ede024&keytyp
e2=tf_ipsecsha
 Adelie Penguins: Af fairs and prostitution
https://www.google.ca/webhp?sourceid=chrome instant&rlz=1C1CHFX_enCA549CA549&ion=1&espv=2&ie=UT
F-8#q=extrapair%20paternity%20in%20adelie%20penguins
(click the researchgate.net one)
 Descent with Modification
http://evolution.about.com/od/Evolution -Glossary/g/DescentWith-Modification.htm
REFERENCES
 Elephants evolving their tusks away
http://news.bbc.co.uk/2/hi/africa/180301.stm
 Descent with Modification
http://animals.about.com/od/d/g/descentwithmodification.ht
m
 Parasitism : Mother Nature is Trying To Kill You by Dan Riskin
 Mutations (Wikipedia Article):
http://en.wikipedia.org/wiki/Mutation#By_effect_on_structur
e
 Mutation FAQ http://www.talkorigins.org/faqs/mutations.html
 Hyena Genitals
http://books.google.ca/books?id=dASsUFtN57sC&pg=PP1&re
dir_esc=y#v=onepage&q=hyena&f=false